1. Field of the Invention
The invention relates to a braking force control device for a vehicle and a braking force control method for a vehicle. More specifically, the invention relates to a braking force control device for a vehicle and a braking force control method for a vehicle in which there is performed front and rear wheel distribution control of a braking force by controlling individually braking pressures of left and right rear wheels such that, during braking, a wheel speed of a rear wheel takes on a value lying within a target control range that satisfies a predefined relationship with respect to a wheel speed of a front wheel.
2. Description of Related Art
Braking force control devices that perform front and rear wheel distribution control of braking force are conventionally available. For instance, Japanese Patent Application Publication No. 10-138895 discloses a braking force control device that controls individually a braking force of rear wheels by controlling individually braking pressures of left and right rear wheels on the basis of a difference between the wheel speed of each rear wheel and the highest wheel speed from among the wheel speeds of the left and right front wheels.
In a vehicle equipped with a conventional braking force control device that performs front and rear wheel distribution control of braking force in the manner of the braking force control device disclosed in JP-A-10-138895 (JP-A-10-138895), braking pressure is controlled through control of control valves such as electromagnetic-type pressure-increasing valves and pressure-decreasing valves, that are provided for each wheel.
The control valves of the left and right rear wheels are controlled individually in front and rear wheel distribution control of braking force wherein the braking pressure of the left and right rear wheels is controlled individually. Accordingly, the operational frequency of the control valves of all the left and right rear wheels is higher than in a case where the control valves of the left and right rear wheels are controlled simultaneously. Therefore, it is not possible to avoid an increased frequency of occurrence of transmission, to a brake pedal and so forth, of vibration and noise generated accompanying the operation of the control valves. Conventional braking force control devices have thus room for improvement in terms of securing sensory quality.